When I delete my history with CCleaner, it deletes the entire 'cache' folder located c:\documents and settings\myname\local settings\application data\mozilla\firefox\profiles\kzkuuskb.default\cache. Firefox internal cleaner does it differently by cleaning the files without deleting them. The bug it's causing is that I have my firefox location bar set to display history only, not bookmarks, but since CCleaner deletes the entire folder, the next time I run firefox the location bar ends up searching the bookmarks I previously visted even though I have it set to search history only. When deleting history through firefox's internal cleaner, this problem doesn't happen. The only fix I have found for this is to delete my bookmarks and reimport them every time.
Sorry if I didn't explain that very clearly.
Thx